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OBIEE 11g Repository Beginners GuideBuilding Logical Dimension Hierarchy

Business always wants to analyze the data in detailed and summary manner. In order to facilitate users to

detail and summary analysis, we need to create the logical dimension hierarchy. This document briefs

you about the building logical dimension. Join our professional training program to learn from the best

History:

Version Description Change Author Publish Date

0.1 Initial Draft Hitesh Mankar 23-09-2011

0.1 1stReview Amit Sharma 23-09-2011

Logical Dimension Hierarchies

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Dimensions are key to navigating the business intelligence system that means dimensions define theaxis of investigation of a fact and hierarchy is a set of parent-child relationships between attributes

within a dimension and key to navigating dimensions.

In OBIEE Logical dimension hierarchy plays a very important role to calculate useful measures and

allows users to drill down for more details.

Logical dimension hierarchies are categories of attributes by which the business is defined. Periods,

products, markets, customers are very common dimensions in business model.

Dimension is mainly about View By, Group by, and Filter By.Each level has at least one logical key, the top level is marked as the grand total level, and you can drag

other attributes in to each level and have OBI EE display those, rather than the level key, when users drill

down in reports.,

First of all Update All Rows Counts check how many rows in every table and last updated state. This

will help you to define level number of members at this level for each level of all the hierarchies

1. Now first step is to create a logical dimension hierarchy, create a logical dimension object. There aretwo methods to create logical dimension objects.

Method1:- Right Click on the Business model in BMM layer select New Object Logical Dimension

Dimension with Level Based Hierarchy.(Here structure is selected as Time because its a time dimension for

other dimension hierarchies dont select Time as structure )

Method2:- Right Click on a logical dimension table and select Create Dimension Dimension with Level-Based Hierarchy, this will create a dimension hierarchy for the selected dimension table

Let`s continue with Method1 to create dimension hierarchies.

2. Start to add a logical level which is highest level of hierarchy. Right click on the logical dimension and

select New Object Logical level.



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3. Give a name to this level select Grand Total Level, basically the first level should be grand total level

(Selecting the Grand total level check box is to indicate that this is the grand total level of this

hierarchy).

4. Now add a child level to dimension hierarchy.

Right-click on the Parent level (Total) and select New Object Child Level.

Give a name for the level and enter the Number of levels at this level.

Now you need to identify the number of elements for each level. The number of elements represents the

distinct count of rows for each level and is used by Oracle BI Server to determine the most efficient way to

access data when picking aggregate sources. The number does not have to be exact, but ratios of numbers

from one level to another should be accurate and you want to enter a larger number for child levels inrespect to parent levels.

Enter number of elements at this level from updated all row counts and enter value that how many rows

year column contains.

5. Similarly add more child levels below this level as shown in below screen shot.



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6. Create Level Keys: - Level keys define the unique elements in each level and provide the context for

drill down. Each level needs to have one or more attributes that compose a level key. The level key defines

the unique elements in each level and provides the context for drill down.

A level may have more than one level key. When that is the case, you need to specify which key is the

primary key of that level. All dimension sources that have aggregate content at a specified level need to

contain the column that is the primary key of that level.

To create Level keys drag a logical column which could be the key for that level.

7. Double-click a level to open the level properties window Click the Keys tab and enter key name

click on the primary keys dropdown select the key name to enable the edit and delete button .

Then click on edit button to open the logical key dialog box for this level. Select a column form

columns to create a key column for this level and select use for display click ok.

8. Check out the changes and assigned key at the level click ok. The color of level key icon will change

and also select check box Use for Display.



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9. Similarly assign keys for each level following above steps.

10. Set the Preferred Drill Path(Optional): - You can use the Preferred Drill Path tab to identify the dril

path to use when Oracle BI Presentation Services users drill down in their data requests. You should use

this only to specify a drill path that is outside the normal drill path defined by the dimensional level

hierarchy. It is most commonly used to drill from one dimension to another. You can delete a logical level

from a drill path or reorder a logical level in the drill path.

To set a preferred drill path for dimension levels Open the properties of the level and select the PreferredDrill Path tab and press ADD button which open the Browse dialog box, where you can select the logical

levels to include in the drill path. You can select logical levels from the current dimension or from other

dimensions.

Check the proffered drill path.



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11. Create Presentation HierarchiesTo create hierarchies in presentation layer follow below methodsMethod 1:- If presentation tables are already exists in Presentation layer. Drag and drop logical

dimension hierarchy into previously creates dimension table to which this hierarchy belongs. Will create

a presentation hierarchy automatically.(Such as drag time dimension hierarchy into D0 Time

presentation table).

1.1) Presentation Table without Presentation hierarchy.

1.2) Drag and drop logical dimension hierarchy from BMM layer into presentation table of Presentation

layer.

Method 2:- If Presentation tables are not exits into presentation layer, Drag and drop the Dimensiontable from BMM layer into Presentation layer, will create a presentation table, columns with presentation

hierarchy automatically.



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Method 3:- Create Presentation Hierarchy manually

Right click on presentation table for which you want to create a presentation hierarchy.

3.1) Select New Object Presentation Hierarchy.

3.2) Give a name into Name field in presentation hierarchy window and click on browse button.

3.3) select a logical dimension hierarchy from BMM layer.

3.4) after that a new presentation layer hierarchy will get created without ant level.

3.5) Now create levels for presentation hierarchy.



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Right click on hierarchy icon Select New presentation level.

3.6) Give name of level and browse to assign level from BMM layer.

3.7) Similarly create or add other levels of presentation layer hierarchy following above steps.

12) Testing Hierarchy into presentation layer (answers)12.1) Create a request select columns (Year and a measure) from left pane.

12.2) Click on result tab to see result. You will get Revenue by year.

12.3) Now click on any value (data) for column (Per_Name_Year) of dimension table and check the result,

drill down is available now and you can see detail result for a specific year which is the top level of

hierarchy.

12.4) Click on next levels values to go for more detail result, you can drill down till low level of hierarchy.

12.5)



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12.6)

12.7)

13. Create Level Based Measures

As per a business requirement need to calculate Total Revenue, Yearly Revenue, Quarterly Revenue etc, at

different levels of dimension and these measure were used later to create shared measure.

13.1) To create a level based measures create a logical column in BMM layer in Fact table and map it from

an existing logical column.

13.2) Select a level from Time Dimension Hierarchy to set it for measure.

13.3) Click ok.



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13.4) Check the measure in BMM layer under FACT table.

13.5) Now add this level based measure into dimension hierarchy, drag and drop the measure or copy and

paste into under the dimension hierarchy.

Following the above steps you can create more level based measures, and no need to repeat the total

calculations like Total Revenue, if the basis is same for different levels, because measure is calculated

automatically at run time to the appropriate level. If the calculation for a level is different from that of

another level need to be have a separate measure or logical column.

14) Crating Share Measure: - Share measures are calculated by taking some measure and divide it by alevel based measure to calculate percentage.

14.1) Create a logical column Go to expression builder Select FunctionsMathematical Functions

Select Round function.

14.2) Select digits and enter a value, select Source Number to create a formula as shown below.

15) Add all these newly created measures to the presentation layer and create a request.



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16) Compare result for all selected column how these columns are showing result.

16.1) Check result and verify with the data , that values in the columns are desired or not.

Here Total Revenue is calculating Total Revenue overall and show same data at each level of dimensionhierarchy but the share (always show round off data) and revenue sum all will get change.

16.2)

16.3)

16.4)

17) Now go back to criteria and create one more request with Presentation Hierarchy to get result in

parent child form.

18) Click on result and check the hierarchy and measure value.

Result will appear in a pivot table view



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18.1) Result for Total, click on + plus sign for Total, it will generate result for year.

18.2) Similarly process result for deep child level (Quarter level)

18.3) Month Level


logical dimensio nhierarchy

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